Embryonic Stem Cells

What we know, from Maureen L. Condic, associate professor of neurobiology and anatomy at the University of Utah School of Medicine in First Things.

The assertion that embryonic stem cells in the laboratory can be induced to form all the cells comprising the mature human body has been repeated so often that it seems incontrovertibly true. What is missing from this assertion remains the simple fact that there is essentially no scientific evidence supporting it. Experiments have shown that embryonic stem cells are able to participate in normal embryonic development, an observation that is also true of cancerous embryonal carcinoma cells. When injected into early mouse embryos, both embryonic stem cells and embryonal carcinoma cells randomly contribute to every tissue of the developing body.

Even more dramatically, when embryonic stem cells are injected into mouse embryos under specific experimental circumstances (a procedure known as tetraploid complementation), they can be induced to form all the cells of the postnatal body. These experiments prove that embryonic stem cells (and embryonal carcinoma cells) remain capable of responding appropriately to the developmental signals that regulate tissue formation in the embryo, and from these results we can conclude that if embryonic stem cells were intended to provide cell replacement therapies for embryos, they would represent a very promising therapeutic approach. The problem, of course, is that embryos are not the intended targets of stem cell therapies, and there is little reason to believe that the capabilities of embryonic stem cells in an embryonic environment are relevant to their therapeutic potential for non-embryonic patients.

Five years ago, most scientists working in the field of embryonic stem cell research confidently predicted that we would soon determine the precise recipe of molecular factors required to replicate in the laboratory the mysterious inner life of the embryo. David Anderson, a stem cell researcher at Caltech, boldly asserted in a New York Times opinion piece that once science had figured out the factors required to replicate embryonic development, specific molecules could simply be “thrown into the bubbling cauldron of our petri dishes,” where they would transform embryonic stem cells into an unlimited source of replacement cells for any tissue we chose to produce.

Skepticism regarding this claim was well warranted. While there have been hundreds of papers published over the past five years that stridently claim “cell type X produced from embryonic stem cells,” under closer inspection these successes have all been less miraculous than they appeared. It is relatively easy to generate stem cell derivatives in the laboratory that have at least some of the properties of normal, mature cell types. But the test of whether an embryonic stem cell–derived brain cell, for example, is indeed a normal adult brain cell is to put it into the brain of an adult animal and determine whether it survives and contributes to normal brain function. In addition, if laboratory-generated cells are to be therapeutically useful for the treatment of human disease and injury, they must be shown to have therapeutic value in adult animals: It is not sufficient that embryonic stem cell–derived cells merely survive in adults; they must also be able to repair the underlying disease or injury. It is precisely this kind of test that embryonic stem cell–derived tissues have proved unable to pass.

Comments

[John Jansen]

Earlier this year I first heard the term "the stem cell hustle".

It's a pity the phrase hasn't yet become widespread.

[Melody]

"The stem cell hustle." Yes. We've had that in spades in our area daily newspaper, for the past several months. There are three basic arguments that are used to press the point for embryonic stem cell research:
1. If you oppose it, then you think a little clump of cells has more rights than people with Alzheimer's, cancer, diabetes, etc.
2. If you oppose stem cell research, you stand in the way of our state university system's ability to attract the best and brightest scientists. We will forever be a provincial backwater.
3. The leftovers from in vitro fertility treatment are going to be discarded anyway so it is just wasteful not to utilize these for medical research.
There is so much erroneous thought here that it is hard to know where to begin to refute it. But it is this last topic that no one wants to touch because everybody knows someone who had children through in-vitro. And yes, children are a blessing no matter how they got here. But unless we think about how very disrespectful this process is to our dignity as human beings, the end is always going to justify the means.

[Julia aka MOM]

The most important thing I got from her article is that even cloning animals is not working well much less are embryonic stem cells from animals producing any results. Before we get into using human embryonic tissue, shouldn't we wait until it works with animals? What's the big rush?

And the thousands of human ova that were harvested in Korea and still no good results.

I think it's universities that want the grant money. Somehow in our culture corporations are villains but universities are always thought to be pure of heart. What a joke!

[Joe Paprocki]

Amy, I love your blog and I often recommend it to people. I know that from time to time you have commented on the state of catechesis in our Church. I am deeply concerned about the quality of catechesis and the formation of catechists. To that end, I have begun a blog for catechists called Catechist's Journey (www.catechistsjourney.org). It is designed to give catechists a place to discuss the challenges of serving the Church as a catechist. It gives me a chance to provide professional support for catechists, something that I have been doing for over 25 years and something that my work at Loyola Press allows me to do on a regular basis. I appreciate anything you can do to encourage catechists to visit my blog so that we can focus on the serious challenges facing us as catechists and find the support, insights, and inspiration we need to serve more effectively. Thanks! -joe paprocki

[Sandra Miesel]

The "stem cell hustle" was used to great effect in the past election. Here in Indiana, my utterly anti-life state rep (who's both an MD and a lawyer) won re-election over a strongly prolife Catholic by cleverly manipulating this very issue. His ads showed sick people and even a sheeted corpse, doomed by forbidding embryonic stem cell research. This individual may be headed for a US Senate run in a few years.

[Kevin Jones]

"3. The leftovers from in vitro fertility treatment are going to be discarded anyway so it is just wasteful not to utilize these for medical research."

Only about ten percent of those IVF embryos have parental approval to be fodder for research.

And egg donation is risky for the donors, who are also more highly paid by IVF clinics.

For such putative utilitarians, ESCR proponets are very unpractical.

[larry davis]

beware of such easy formulations.

thelrd in TEXAS